Differences in effects of age and blood pressure on augmentation index

The effect of age on the augmentation index (AI) differs between young adults and the elderly, and the AI reaches a plateau after the age of 60 years. We examined whether the effects of age and an elevation in blood pressure on the AI differ between young adults and the elderly, between subjects with and without high blood pressure, or between subjects with and without a high AI.

The radial AI was measured in 10,190 subjects who were either healthy or had hypertension (n = 5,477 men and 4,743 women).

In both sexes, a phased increase in the radial AI with age could only be confirmed up to an age of 60 years. A phased increase in the radial AI with the systolic blood pressure (SBP) could be confirmed up to an SBP of >170 mm Hg. Among subjects categorized within the highest age tertile, the highest SBP tertile, or the highest radial AI tertile, stepwise multivariable analyses demonstrated that SBP, but not age, was a significant independent factor influencing the radial AI.

The effect of age and blood pressure on AI differ not only between young adults and the elderly but also between those with and those without high blood pressure or between those with and those without a high AI. The effect of an elevation in blood pressure, but not aging, on the AI is significant in the elderly, in subjects with high blood pressure, or in those with a high AI.